FRAME STRUCTURE OF A FOLDABLE CHAIR

Abstract: The invention relates to a frame structure for a foldable chair comprising a seat part (1) and a back rest part (2) swingably connected to the rear end of the seat part, whereby the back rest part (2) further is swingably connected to both arm rest parts (3) of the chair at a distance from the point of articulation (5) between the back rest (2) and the seat part (1) which seat part adjacent to each arm rest part (3) is provided with a glide (6) extending in a diagonally forward and upward direction which glides are arranged to cooperate with a locking and/or bearing box (7) rotatably connected to the corresponding arm rest part (3). The frame structure is characterized in that the frame of the arm rest part (3) is a mainly Z-shapedly bended and relatively thin metal sheet, whereby an upper horizontal shoulder (9) of the metal sheet forms the arm rest proper and a lower horizontal shoulder (10) thereof forms a fixing plate for a frame support (11) or a swing means of the chair.

Description: Frame Structure of a Foldable Chair The invention relates to a frame structure for a foldable chair, comprising a seat part and a back rest part swing- ably connected to the rear end of the seat part, whereby the back rest part further is swingably connected to both arm rest parts of the chair at a distance from a point of articulation between the back rest and the seat part, which seat part, adjacent to each arm rest part is provi- ded with a glide extending diagonally in a forward and upward direction, which glides are arranged to cooperate with a locking and/or bearing box rotatively connected to the corresponding arm rest part. In previously known frame structures of the above men¬ tioned type, both arm rest parts have been built up of flat irons welded in a mainly keystone shaped frame structure, to which an ordinary arm rest made of wood is secured by screws. Further, both of the arm rest parts are connected to each other by means of a transversal metal rod. A frame structure of this shape has a relati¬ vely high weight and, at the same time, it requires a very much labour consuming manufacturing process. An object of the present invention is to provide a light and simple frame structure being fast and simple to pro¬ duce and comprising a significantly reduced number of components. This object is achieved by providing a frame structure characterized in that the frame of the arm rest part is a mainly Z-shapedly bended thin metal sheet, whereby an upper horizontal shoulder of the metal sheet forms the arm rest proper and a lower horizontal shoulder thereof forms a fixing plate for a frame support or a swing means of the chair. In a frame structure according to the present application a lot of welding work will be eliminated, which signifi¬ cantly will reduce the manufacturing costs. Further cha¬ racteristics of the invention will appear from the at- tached dependent claims 2 to 5. In the following, the invention will be described in more detail by reference to the attached drawings, in which: Fig. 1 shows a side view of an example of a frame struc¬ ture according to the invention; Fig. 2 shows the frame structure seen from above; and Fig. 3 shows a front view of the frame structure. The present frame structure for a foldable chair com¬ prises a seat part 1 and a back rest part 2 swingably connected to the rear end of the seat part 1. Further, the back rest part 2 is swingably connected to both arm rest parts 3 of the chair, preferably around a horizontal axle 4 in an upper rear corner of each arm rest part 3, at a distance from the point of articulation 5 between the back rest 2 and the seat part 1. The seat part 1, on the other hand, is slidably suspended in both of the arm rest parts 3 of the chair by means of a pair of glides 6 extending diagonally in a forward and upward direction and solidly fastened to the corresponding sides of the seat part 1, which glide 6 cooperates with a locking and/or bearing box 7 turnably connected to the correspon¬ ding arm rest part 3. When the locking member of the locking and/or bearing box 7 is activated, the glide 6 is arranged to slide along the locking and/or bearing box 7. In the drawing, the chair is shown in an upright posi- tion. When one wish to change the position of the chair the locking member of the locking and/or bearing box 7 is activated by a control means provided on the arm rest part 3 whereby the glide 6 is unlocked and is able to slide along the locking and/or bearing box 7. When you, sitting in the chair, press the upper portion of the back rest part 2 slightly backwards the back rest 2 will swing around its axle 4 in the upper rear corner of the arm rest part 3 pushing simultaneously the seat part 1 for¬ wards, which part 1, supported by the pair of glides 6, will move forwards and diagonally upwards. Such a suspension of the back rest part 2 and the seat part i will have a very stabilizing influence on the fra¬ me structure proper of the chair, which feature have gi¬ ven the idea to this invention to simplify the structure of the frame structure of the chair. This aim has been achieved by producing the whole frame of the arm rest part 2 as a mainly Z-shapedly bended and relatively thin metal sheet. A required strength of the construction is obtained by the above described suspension of the seat part 1 and the back rest part 2. The upper horizontal shoulder 9 of the arm rest part 2, which shoulder extends outwardly from the chair is the arm rest proper of the chair, while the lower horizontal shoulder 10 is a fixing plate for a frame support 11 or a swing means of the chair. For this purpose, a number of fixing holes are incorporated in said lower shoulder 10. Locking and/or bearing box 7 is fastened rotatively to the vertical por¬ tion of the arm rest part 3, preferably via a fixing pla¬ te 12, which will further increase the stability. In order to achieve a best possible strength in the ben¬ ded metal sheets, it is advantageous to press a number of stabilizing bulgings 13 i the area around each bending. In the embodiment according to the drawing, the arm rest part 3 includes four bulgings 13 at the upper bending and three bulgings 13 at the lower bending. A possible sideways deviation in the frame structure can preferably be counterworked by a pair of plastic pads 14, or the like, being applied on both sides of the seat part 1. These plastic pads 14 are arranged to fill up the spa- ce between the seat part 1 and the arm rest part 3, with¬ out leaving any gap therebetween. By using relatively hard plastic pads 14 the possible sideways deviation in the frame structure of the chair will be efficiently eli¬ minated. A preferable position of these plastic pads 14 is in the area around the rear fixing point of each glide 6 in the seat part 1. Connection of the sitting assembly, i.e. the seat part 1, the back rest part 2, and the arm rest parts 3 to the frame support 11 or the swing means of the chair is pre¬ ferably carried out by an H- or I-formed frame secured by srews to the lower shoulder 10 of both arm rest parts 3 which frame possibly via a cradle is connected to a ver¬ tical swinging axle of the chair. The frame structure of the chair is cushioned and up¬ holstered in a suitable way in order to give it a best possible sitting comfort and an esthetic appeal.

Claims: Claims 1. A frame structure for a foldable chair comprising a comprising a seat part (1) and a back rest part (2) swingably connected to the rear end of the seat part, whereby the back rest part (2) further is swingably con¬ nected to both arm rest parts (3) of the chair at a dis¬ tance from a point of articulation (5) between the back rest (2) and the seat part (1), which seat part, adjacent to each arm rest part (3) is provided with a glide (6) extending diagonally in a forward and upward direction, which glides are arranged to cooperate with a locking and/or bearing box (7) rotatively connected to the cor¬ responding arm rest part (3), characterized in that the frame of the arm rest part (3) is a mainly Z-shapedly bended thin metal sheet, whereby an upper horizontal shoulder (9) of the metal sheet forms the arm rest proper and a lower horizontal shoulder (10) thereof forms a fi¬ xing plate for a frame support (11) or a swing means of the chair. 2. A frame structure according to claim 1, characterized in that the arm rest component (3) at both of the ben- dings is equipped with a number of bulgings (13). 3. A frame structure according to claim 2, characterized in that the locking and/or bearing box (7) is fixed to the vertical portion of the arm rest part (3) by a fixing plate (12). 4. A frame structure according to claim 3, characterized in that the seat part (1) in connection to each glide (6) is provided with a plastic pad (14) extending in sideways direction to the corresponding arm rest part (3). 5. A frame structure according to claim 4, characterized in that connection to the frame support (11) or to the swing means of the chair is carried out via an H- or I- formed frame secured by screws to both of the arm rest parts (3), which frame possibly via a cradle may be con¬ nected to a vertical swinging axle of the chair.

Inventors: KJELLMAN FREDRIK, KJELLMAN, FREDRIK
Applicants: MEKRAPID
Application year: 1994
Main classification: A47C1
IPC codes: A47C1